Pretest Flashcards
True or False
Residential and commercial AC outlets are connected in series so that all connected devices receive the same voltage?
False
Select which fuse would be the BEST choice for a 12Vdc, 2.5W camera?
a) 1/8A
b) 1/4A
c) 1/2A
d) 1A
c) 1/2 is best
What voltages can be created using a 9V battery and a 1.5V battery in series?
a) 10.5Vdc
b) 7.5Vdc
c) 10.5Vdc and 7.5Vdc
d) 9Vdc and 1.5Vdc
c) 10.5Vdc and 7.5Vdc
An oscilloscope measures_______ on its horizontal axis and ________ on its vertical axis?
a) Resistance, Capacitance
b) Current, Wattage
c) Time, Voltage
d) Voltage, Frequency
c) Time, Voltage
Another way to express 123,000,000 mV would be:
a) 123,000 V
b) 123kV
c) .123MV
d) all the above
d) all the above
If you place a 5k Ohm resistor in a circuit that will apply 120V across it, what size (wattage) resistor will you need?
a) 1/2 watt
b) 1 watt
c) 2 watt
d) 5 watt
d) 5 Watt
Assuming equal lengths of wire, which gauge has the greatest amount of electrical resistance?
a) 6
b) 12
c) 18
d) 24
d) 24
After installing BNC connectors on a 4 foot length of RG-59 cable, the Fluke 177 gives a reading of 0 Ohms from the center conductor to shield.
a) normal reading, cable is ready to use
b) normal reading, check center conductor end to end before using
c) abnormal reading, meter should show an open circuit (OL)
d) abnormal reading, meter should show 75 ohms
c) Abnormal reading, meter should show an open circuit (OL)
Which of the following are true about series circuits?
A) as you add series resistance the current goes up
B) The voltage dropped across each resistor is always the same.
C) Current is the same through out the circuit.
D) The sum of all the voltage drops in a circuit will equal source voltage.
C and D
The “difference of potential” is also known as?
Voltage
True or False
A physically larger resistor can dissipate more heat than a small resistor made of the same material; therefore, the larger the resistor has a higher wattage rating.
True
Frequency is measured in what units?
Hertz
True or False
In a series circuit a larger resistor has a larger voltage drop.
True
True or False
In a series circuit a larger resistance has a larger Power drop.
True
True or False
In a series circuit, the total voltage, Vt, is the sum of all voltage drops.
True
In Series, an open circuit, will have a total Current of ___________.
0 (Zero)
True or False
In a Series, an open circuit will have zero voltage dropped across each good component.
True
10mA equals how many Amps?
a) .001
b) .10
c) .01
c) .01 Amps
How many kilovolts is 15V?
a) .15 kV
b) .015 kV
c) 1.5 kV
b) .015 kV
How many micro Amps is .00025 Amps?
a) 250 uA
b) .25 mA
c) 25 nA
a) 250 uA
When measuring resistance using the Fluke 177 DMM, the display shows ______ for a short circuit and _____ for an open circuit?
a) 0 ohms, 10 ohms
b) 5k ohms, OL
c) OL, 15 Mohms
d) 0 ohms, OL
d) 0 ohms, OL
Which of the following is true of parallel circuits? (all that apply)
a) as you add parallel resistance the current total (I t goes up)
b) each resistance will have the same voltage drop
c) current is the same for all parallel branches regardless of resistance values
d) voltage drops across parallel branches vary, but added together equal source
a) as you add parallel resistance the current total (I t goes up)
b) each resistance will have the same voltage drop
A common gauge wire used for an electrical outlet in a home is?
a) 14 gauge
b) 18 gauge
c) 22 gauge
d) 0 gauge
a) 14 gauge
Using ohms law, if the supply voltage of a circuit is fixed and the resistance goes up, the current must:
a) go down
b) stay the same
c) go up
d) none of the above
a) go down
True or False
When wiring a simple “one way” AC switch in your house, the standard method is to attach the neutral wires to the switch.
False
What size circuit breaker is needed for an electrical clothes dryer that consumes 5000 watts at 240 VAC?
a) 15 amp
b) 20 amp
c) 30 amp
d) 10 amp
c) 30 amp
The schematic symbol below represents: | | ----- + -- ----- -- - | |
a) battery
b) resistor
c) capacitor
d) cell
a) battery
Four D cell batteries connected in series will give a potential difference of:
a) 1.5v
b) 3v
c) 6v
d) 10v
c) 6v
True or False
The most important specifications of a power supply are voltage and current.
True
Audio is considered a(n):
a) AC signal
b) DC signal
c) Fixed Frequency
d) Positive DC voltage
a) AC signal
True or False
A 19 AWG (American Wire Gauge) conductor has a lower current carrying capacity than a 24 AWG conductor.
False
Power in an electronic circuit, is expressed in what unit of measure?
a) Watt
b) Ohm
c) Volt
d) Amp
a) Watt
True or False
Series circuits only have one path for current to flow.
True
True or False
Current in a series circuit is the same throughout the circuit.
True
Yes or No
Does the positive terminal attract electrons as much as the negative terminal repels them?
Yes
Yes or No
Do all electrons have the same speed leaving and entering battery?
Yes
Does a larger resister have a larger or smaller Voltage drop?
larger
Does a larger resistance have a larger or smaller Power drop?
larger
Yes or No
In a series circuit, does the Total Voltage equal the sum of all Voltage drops?
Yes
Select all that apply to a Series Open Circuit:
a) Total Current equals zero
b) 0V dropped across each good component
c) source voltage across the open
d) all the above
d) all the above
Select all that applies in a Series Short Circuit:
a) Current increases above normal
b) Each good component drops more Voltage
c) 0V dropped across the shorted component
d) all the above
d) all the above
Is a multimeter connected in series or parallel to measure current?
Series
Does a multimeter in current mode have a very high or low resistance?
very low resistance
True or False
In a series circuit a defective component will have voltage drop that changes in the opposite direction when compared to all the good components.
True
Yes or No
In a series circuit, if one component is open, is there current in the circuit?
No
How is a voltage measurement taken?
Voltage is difference of potential between two points in a circuit.
Meter is placed across or in parallel with the circuit.
Note: Meter is a high resistance load of 10M ohm connected to the circuit.
How is a resistance measurement taken?
Meter provides the battery source for the measurement.
Device to be measured must be isolated from the circuit, so disconnect one side or remove all together from the power source.
Place meter leads across device to be measured.
How do you take a current measurement?
Current is measured by opening the circuit and then restoring the open by placing the meter in series.
Remember to move the red probe to the appropriate port and toggle the yellow button for DC on the Fluke DMM.
How do you check the health of the Fluke fuses?
Set the selector to ohms position and using the red lead placed in the V/ohms port to probe the mA/A ports. A reading of OL equals a bad fuse.
